Down-regulation of IFIT3 protects liver from ischemia-reperfusion injury

Combining WGCNA and machine learning to identify mechanisms and biomarkers of ischemic heart failure development after acute myocardial infarction

Background

Ischemic heart failure (IHF) is a serious complication after acute myocardial infarction (AMI). Understanding the mechanism of IHF after AMI will help us conduct early diagnosis and treatment.

Methods

We obtained the AMI dataset GSE66360 and the IHF dataset GSE57338 from the GEO database, and screened overlapping genes common to both diseases through WGCNA analysis. Subsequently, we performed GO and KEGG enrichment analysis on overlapping genes to elucidate the common mechanism of AMI and IHF. Machine learning algorithms are also used to identify key biomarkers. Finally, we performed immune cell infiltration analysis on the dataset to further evaluate immune cell changes in AMI and IHF.

Results

We obtained 74 overlapping genes of AMI and IHF through WGCNA analysis, and the enrichment analysis results mainly focused on immune and inflammation-related mechanisms. Through the three machine learning algorithms of LASSO, RF and SVM-RFE, we finally obtained the four Hub genes of IL1B, TIMP2, IFIT3, and P2RY2, and verified them in the IHF dataset GSE116250, and the diagnostic model AUC = 0.907. The results of immune infiltration analysis showed that 8 types of immune cells were significantly different in AMI samples, and 6 types of immune cells were significantly different in IHF samples.

Conclusion

We explored the mechanism of IHF after AMI by WGCNA, enrichment analysis, and immune infiltration analysis. Four potential diagnostic candidate genes and therapeutic targets were identified by machine learning algorithms. This provides a new idea for the pathogenesis, diagnosis, and treatment of IHF after AMI.

Knockdown of IFIT3 ameliorates multiple sclerosis via selectively regulating M1 polarization of microglia in an experimental autoimmune encephalomyelitis model

The key to the treatment of multiple sclerosis (MS) is to promote the transition from inflammation-induced demyelination to remyelination. Polarization of microglia towards M1 or M2 phenotype is critical in this transition. Interferon induced protein with tetratricopeptide repeats 3 (IFIT3) is involved in inflammatory reaction and up-regulated in M1-polarized macrophages. However, its effect on microglia during MS has not been reported. In this paper, we demonstrated the important role of IFIT3 in selectively regulating microglia polarization. The expression of IFIT3 was increased when microglia were polarized towards M1, but did not change under M2 polarization. The knockdown of IFIT3 selectively inhibited M1 polarization, while M2 polarization was not affected by IFIT3 silencing. Furthermore, the activation of signal transducer and activator of transcription 1 (STAT1) and nuclear factor kappa-B (NF-ĸB) signaling in M1 polarized microglia was suppressed by downregulating IFIT3. In experimental autoimmune encephalitis (EAE) mice, an animal model of MS, IFIT3 expression was upregulated. The disease progression, inflammatory infiltration and demyelination in the EAE mice were alleviated by silencing IFIT3. The inhibitory effects of IFIT3 knockdown on M1 polarization and STAT1 and NF-ĸB pathways were also confirmed in the spinal cord of EAE mice. In summary, our findings suggest that IFIT3 selectively intensified microglia polarization towards the pro-inflammatory M1 phenotype, and may contribute to the progression of MS.

The emerging roles of IFIT3 in antiviral innate immunity and cellular biology

The interferon-inducible protein with tetrapeptide repeats 3 (IFIT3) is one of the most important members in both the IFIT family and interferon-stimulated genes family. IFIT3 has typical features of the IFIT family in terms of gene and protein structures, and is able to be activated through the classical PRRs-IFN-JAK/STAT pathway. A variety of viruses can induce the expression of IFIT3, which in turn inhibits the replication of viruses, with the underlying mechanism showing its crucial role in antiviral innate immunity. Emerging studies have also identified that IFIT3 is involved in cellular biology changes, including cell proliferation, apoptosis, differentiation, and cancer development. In this review, we summarize the characteristics of IFIT3 with respect to molecular structure and regulatory pathways, highlighting the role of IFIT3 in antiviral innate immunity, as well as its diverse biological roles. We also discuss the potential of IFIT3 as a biomarker in disease diagnosis and therapy.

IFIT3 Is Increased in Serum from Patients with Chronic Hepatitis B Virus (HBV) Infection and Promotes the Anti-HBV Effect of Interferon Alpha via JAK-STAT2 In Vitro

Increasing evidence indicates that interferon alpha (IFN-α) therapy is an effective treatment option for a subgroup of patients with chronic hepatitis B virus (HBV) infection. It has been confirmed that interferon-induced protein with tetratricopeptide repeats 3 (IFIT3), a member of the interferon-stimulated genes (ISGs), could inhibit the replication of various viruses. However, its effect on HBV replication is unclear. The present study sought to explore the role and mechanism of IFIT3 in IFN-α antiviral activities against HBV. IFIT3 mRNA levels in the peripheral blood of 108 treatment-naive patients and 70 healthy controls were analyzed first. The effect of IFIT3 on the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway under the dual intervention of IFN-α and HBV was also explored in vitro. Treatment-naive individuals exhibited elevated levels of IFIT3 mRNA compared to the controls (P < 0.0001). Mechanistically, the knockdown of IFIT3 inhibited the phosphorylation of signal transducer and activator of transcription 2 (STAT2), whereas the overexpression of IFIT3 produced the opposite effect in vitro. Meanwhile, the overexpression of IFIT3 enhanced the expression of IFN-α-triggered ISGs, including myxovirus resistance A (MxA), 2'-5'-oligoadenylate synthetase 1 (OAS1), and double-stranded RNA-activated protein kinase (PKR), while a weaker induction of IFN-α-triggered ISGs was observed in ruxolitinib-treated cells. After decreasing IFIT3 expression by validated small hairpin RNAs (shRNAs), the levels of hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and HBV DNA secreted by HepG2 cells transiently transfected with the pHBV1.2 plasmid were increased. Our findings suggest that IFIT3 works in a STAT2-dependent manner to promote the antiviral effect of IFN-α through the JAK-STAT pathway in HBV infection in both human hepatocytes and hepatocarcinoma cells. IMPORTANCE Our study contributes new insights into the understanding of the functions and roles of interferon-induced protein with tetratricopeptide repeats 3 (IFIT3), which is one of the interferon-stimulated genes induced by hepatitis B virus infection in human hepatocytes and hepatocarcinoma cells, and may help to identify targeted genes promoting the efficacy of interferon alpha.

Integrative bioinformatic analysis identified IFIT3 as a novel regulatory factor in psoriasis

Psoriasis is an autoimmune skin disease with poor prognosis. Currently, there is no cure for psoriasis and the pathogenic mechanism of psoriasis remains unclear. Our study aims to explore key regulators underlying psoriasis and potential targets for psoriasis treatment. RNA-seq data of psoriasis and normal tissues were extracted from Gene Expression Omnibus database to screen differentially expressed genes (DEGs). Weighted correlation network analysis (WGCNA) was conducted to identify key gene modules correlated with psoriasis. Enrichment analysis was used to characterize identified genes. The expression of identified genes was verified in a data set with various types of psoriasis lesion tissues and six psoriasis and healthy control tissues by quantitative polymerase chain reaction and immunohistochemistry assays. And the biological functions of IFIT3 in keratinocytes were determined by colony formation assays, Cell Counting Kit-8, and enzyme-linked immunosorbent assays. A total of 594 overlapped genes (370 upregulated and 224 downregulated) were selected as DEGs between psoriasis and normal tissues in three independent data sets. These genes were enriched in interferon-related pathway and cytokine-related pathway. Weighted correlation network analysis identified several gene modules that were associated with psoriasis. Overlapped genes between gene modules and DEGs were associated with interferon-related pathway and T cell activities. Among these genes, OAS1, USP18, and IFIT3 had higher expression levels in psoriasis vulgaris (PV) and nonpustular palmoplantar psoriasis (NPPP) tissues but not Palmoplantar Pustular Psoriasis (PPPP). Meanwhile, these results were confirmed in our independent psoriasis tissue cohort. And results of in vitro experiments showed that inhibition of IFIT3 significantly impaired the proliferation capacity and CXCL1, CCL20, IL-1β, and IL-6 secretion of keratinocytes. Our study identified key genes and pathways underlying the pathogenesis of psoriasis through the conduct of integrated analysis. OAS1, USP18, and IFIT3 could be potential targets for the treatment of psoriasis. IFIT3 can promote the proliferation and immune activation of keratinocytes and facilitates the development of psoriasis.

Downregulation of IFIT3 relieves the inflammatory response and myocardial fibrosis of mice with myocardial infarction and improves their cardiac function

Myocardial infarction (MI) is a common cardiovascular disease with high morbidity and mortality. In this study, we explored the role of interferon-induced protein with tetratricopeptide repeats 3 (IFIT3) in MI. MI was induced by ligation of the left anterior descending coronary artery. Lentivirus-mediated RNA interference of IFIT3 expression was performed by tail vein injection 72 h before MI modeling. Cardiac injury indexes and inflammatory response were examined 3 days after MI. Cardiac function indexes, infarct size, and cardiac fibrosis were assessed 4 weeks after MI. IFIT3 expression was upregulated in myocardial tissues at both 3 days and 4 weeks after MI. Knockdown of IFIT3 significantly relieved the myocardial injury, as evidenced by the decrease in serum levels of cTnI and CK-MB. In addition, IFIT3 knockdown significantly reduced the number of CD68⁺ macrophages and the levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α, indicating that the inflammatory response was relieved. Moreover, IFIT3 silencing also significantly improved cardiac function and reduced infarct size, myocardial fibrosis, and collagen content in mice with MI. Mechanically, the present study showed that the activation of the mitogen-activated protein kinase (MAPK) pathway was observed in myocardial tissues of MI mice, which was blocked by IFIT3 knockdown, as indicated by the decreased phosphorylation of JNK, p-38, and ERK. Collectively, our results revealed the role of IFIT3 in the inflammatory response and myocardial fibrosis after MI, indicating that IFIT3 might be a potential target for MI treatment.

Age-dependent loss of induced regulatory T cell function exacerbates liver ischemia-reperfusion injury

Previous studies demonstrate that the number of induced regulatory T cells (iTregs) increases in aged mice. However, these studies do not characterize iTregs across different ages or how these immune modulators contribute to the dysregulation of immunity in murine disease models. Therefore, this study aimed to examine the relationship between age and iTreg function using a mouse model of hepatic ischemia-reperfusion injury (IRI). In this model, aged-mice suffered more serious injury than Young-mice, with higher serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and higher histological scores from liver biopsies. iTregs isolated from Young-mice exhibited stronger immunosuppressive ability in vitro and had a greater response during IRI in vivo. In addition, aged-mice that were pretreated with iTregs generated in Young-mice (Y-iTregs) had alleviated injury compared with mice pretreated with iTregs from aged-mice (A-iTregs) or no treatment group. Adoptive transfer of iTregs ameliorated liver IRI and promoted liver recovery with decreased levels of interferon-γ (IFN-γ) and interleukin-17 (IL-17). These results demonstrate that the exacerbated IRI observed in aged-mice is a result of decreased iTreg function. Therefore, improving iTreg function is important for disease treatment in elder patients.